Compositions containing polycarbonate

ABSTRACT

Compositions containing polycarbonate and one or more esters derived from a linear carboxylic acid and branched alcohol are disclosed. The inventive compositions feature improved processing properties and are especially suitable for preparing extruded articles.

[0001] The present invention concerns compositions containingpolycarbonate and esters of a linear carboxylic acid and a branchedalcohol, together with products manufactured from these compositions.

[0002] Compositions containing polycarbonates are commonly usedplastics. They are utilised in many different areas. A wide variety ofproducts, including sheets, are produced from the compositions by meansof conventional processing methods, such as injection moulding orextrusion.

[0003] In addition to polycarbonate, the compositions conventionallycontain other components that improve the properties of the composition.Examples of these include lubricants. Carboxylic acid esters, forexample, are used as lubricants.

[0004] Compositions containing polycarbonate and Guerbet alcohols areknown. Guerbet alcohols are the products of the Guerbet reaction.

[0005] Polycarbonate sheets are known for example from EP-A 0 110 221and are produced for a variety of applications. Polycarbonate sheets aremanufactured for example by extrusion of compositions containingpolycarbonate.

[0006] Coextrusion with compositions that contain polycarbonate and thatadditionally contain UV absorbers is possible.

[0007] One problem that arises during extrusion of such sheets is thedeposition of volatile components from the moulding composition on thecalibrator (in the case of multi-wall sheets) or on the rolls (in thecase of solid sheets), which can lead to surface defects on the sheets.Examples of volatile components include UV absorbers, mould releaseagents and other low-molecular components of the compositions.

[0008] EP-A 0 320 632 describes coextruded sheets consisting ofcompositions that contain polycarbonate, contain a UV absorber and cancontain a lubricant. Disadvantageously, with extended extrusion of thecomposition according to EP-A 0 320 632 to form sheets, the surface ofthe sheets is adversely influenced by evaporations from the melt ofcompositions. During coextrusion the increased evaporation of the UVabsorber from the melt of compositions leads to the formation ofdeposits on the calibrator or on the rolls and ultimately to theformation of defects on the surface of the sheets (e.g. white spots,waviness, etc.). On the calibrator, polycarbonate abrasion can, alsolead to powdery deposits on the coextruded polycarbonate sheets.

[0009] Compositions consisting of esters of Guerbet alcohols andpolycarbonates are also known. EP-A 0 390 994, for example, describescompositions containing special fatty acid esters of Guerbet alcohols asmould release agents.

[0010] EP-A 0 649 724 describes a process for the production ofmulti-layer sheets from branched polycarbonates with average molecularweights {overscore (M)}_(w) of 27,000 g/mol to 29,500 g/mol bycoextrusion of a core layer and at least one outer layer with 1 to 15wt. % of a UV absorber. If the mould release agents glycerolmonostearate, pentaerythritol tetrastearate or mixtures thereof asdescribed in EP-A 0 300 485 are used in the compositions for productionof these plastic sheets, the surface of the sheets neverthelessdeteriorates over time.

[0011] It is known from WO 99/05205 that mixtures of mould releaseagents, consisting of fatty acid esters of pentaerythritol and glycerolfor example, can be used to minimise the formation of deposits on thecalibrator or on the rolls, which leads to the formation of defects onthe surface of the sheets (e.g. white spots, waviness, etc.).

[0012] The object of the present invention is therefore to providecompositions containing polycarbonate that do not display the specifieddisadvantages of the compositions known from the prior art.

[0013] The object according to the invention is achieved by compositionscontaining polycarbonate and one or more different compounds with thegeneral formula (I)

[0014] wherein

[0015] a equals 1 to 20,

[0016] b equals 1 to 25 and

[0017] c equals 10 to 40.

[0018] The object according to the invention is further achieved by thecompositions cited in the previous paragraph, whereby these additionallycontain one or more different compounds with the general formula (I)

[0019] wherein

[0020] a equals 0,

[0021] b equals 1 to 25 and

[0022] c is 10 to 40.

[0023] In the case where a=1 to 20, b preferably equals 4 to 20 and c 10to 24.

[0024] In the case where a=0, b preferably equals 4 to 20 and c 10 to24.

[0025] Such compositions are preferred in which the proportion ofcompounds according to formula (I) is 0.02 to 1.0 wt. %, particularly0.05 to 0.5 wt. %.

[0026] Such compositions are further preferred which additionallycontain 0.01 to 0.5 wt. % of esters or partial esters, preferably fattyacid esters or fatty acid partial esters, of tetrahydric to hexahydricalcohols.

[0027] Such compositions are further preferred which additionallycontain 0.1 to 15 wt. % of UV absorbers. The UV absorbers are preferablychosen from the group consisting of(bis[2-hydroxy-5-tert-octyl-2-(benzotriazol-2-yl)phenyl]methane),2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyl)oxyphenol and2-cyano-3,3-diphenyl propenoicacid-2,2-bis[[2-cyano-1-oxo-3,3-diphenyl-2-propenyl)oxy]methyl]-1,3-propanediylester.

[0028] Such compositions are further preferred which additionallycontain 10 to 3000 ppm of heat stabilisers relative to the totalquantity of composition. The heat stabiliser is preferably chosen fromthe group consisting of tris(2,4-di-tert-butylphenyl)phosphite andtriphenyl phosphine.

[0029] The object according to the invention is further achieved by useof compounds with the general formula (I)

[0030] wherein

[0031] a equals 1 to 20,

[0032] b equals 1 to 25 and

[0033] c equals 10 to 40,

[0034] to produce compositions containing polycarbonate and compoundswith the general formula (I).

[0035] The object according to the invention is further achieved by theuse of the compositions according to the invention to manufactureproducts containing these compositions.

[0036] The object according to the invention is further achieved by aprocess for the manufacture of products containing at least one outerlayer containing the compositions according to the invention byextrusion or coextrusion.

[0037] The object according to the invention is further achieved byproducts containing the compositions according to the invention. Theseproducts are preferably sheets, roofing elements or glazing elements.

[0038] The object according to the invention is further achieved by amulti-layer product comprising a first layer containing polycarbonateand a second layer containing one of the previously mentionedcompositions.

[0039] The object according to the invention is further achieved by aprocess for the manufacture of the specified multi-layer products bycoextrusion.

[0040] The object according to the invention is further preferablyachieved by a greenhouse, a conservatory, a bus shelter, an advertisinghoarding, a sign, a safety screen, automotive glazing, a window or aroof containing a multi-layer product according to the invention.

[0041] The multi-layer products according to the invention containpreferably 0.1 to 15 wt. % of a UV absorber. They preferably contain 3to 8 wt. % of a UV absorber.

[0042] The products according to the invention and the multi-layerproducts according to the invention are preferably solid sheets orcorrugated sheets. Both the solid and the corrugated sheets preferablyexhibit on one or both outer sides a layer consisting of thecompositions according to the invention.

[0043] The products or multi-layer products according to the inventionare preferably multi-wall sheets or multi-wall profiles, constructedaccording to the tongue-and-groove system, for example. These preferredproducts or multi-layer products likewise preferably exhibit on one orboth outer sides an outer layer consisting of the compositions accordingto the invention.

[0044] In a further preferred embodiment of the present invention themulti-layer products according to the invention are characterised inthat at least two layers consist of the compositions according to theinvention, whereby the first sheet contains 0.1 to 15 wt. %, preferably3 to 8 wt. % of a UV absorber and the second sheet contains 0.02 to 1.0wt. % of a UV absorber.

[0045] In the compositions according to the invention the proportion ofcompounds according to formula (I) is preferably 0.02 to 1.0 wt. %,particularly preferably 0.05 to 0.5 wt. %, most particularly preferably0.1 to 0.4 wt. %.

[0046] Preferred compounds according to the invention with the generalformula (I), in which a=1 to 20, b=1 to 25 and c=10 to 40, are those inwhich a=1 to 10, b=4 to 20 and c=10 to 24.

[0047] Preferred compounds according to the invention with the generalformula (I), in which a=0, b=1 to 25 and c=10 to 40, are those in whicha=0, b=4 to 20 and c=10 to 24.

[0048] The compositions according to the invention preferablyadditionally contain 0.1 to 15 parts by weight, preferably 3 to 8 partsby weight of UV absorbers.

[0049] The compositions according to the invention preferably contain 80to 99.8 wt. % polycarbonate.

[0050] The compositions according to the invention preferably containbisphenol A homopolycarbonate as polycarbonate.

[0051] The compositions according to the invention can additionallycontain further conventional processing aids, particularly mould releaseagents and flow control agents as well as further conventionalstabilisers, particularly heat stabilisers.

[0052] The compositions according to the invention and the productsmanufactured therefrom can further contain organic dyestuffs, inorganiccoloured pigments, fluorescent dyestuffs and particularly preferablyoptical brighteners.

[0053] Compounds with the general formula (I) are commerciallyavailable. They are conventionally used in the cosmetics sector. Theycan for example be obtained under the trade name Cetiol G 20 S fromCognis (Deutschland, Düsseldorf).

[0054] Compounds with the general formula (I) can be manufactured byconventional processes known to the person skilled in the art. Thecompounds with the general formula (I) are esters of linear carboxylicacids and alcohols branched in the β position. These esters can forexample be produced by esterification of the carboxylic acids andalcohols by known methods. The branched alcohols can be described asGuerbet alcohols. Guerbet alcohols are the products of the Guerbetreaction and can for example be produced by the Guerbet reaction. Theauto-condensation of alcohols under the influence of sodium or copper atapprox. 200° C. and under elevated pressure is known as the Guerbetreaction.

[0055] The compositions according to the invention demonstrate numerousadvantages. They can be readily processed and display no impairments inthe articles obtained as product, such as sheets. Surprisingly it hasbeen found that with the use of the compounds according to formula (I),even further additives known to be volatile no longer lead to theproblems described in the introduction when used in compositionscontaining polycarbonate.

[0056] Polycarbonates according to the invention are homopolycarbonates,copolycarbonates and thermoplastic polyester carbonates. They preferablyhave average molecular weights {overscore (M)}_(w) of 18,000 to 40,000g/mol, preferably from 26,000 to 36,000 g/mol and particularly from28,000 to 35,000 g/mol, determined by measuring the relative solutionviscosity in dichloromethane or in mixtures of equal quantities byweight of phenol and o-dichlorobenzene adjusted by light scattering.

[0057] In the case of multi-layer products the melt viscosity of thecoextrusion layers should preferably be lower than that of the substrateto which they are applied.

[0058] In regard to the manufacture of polycarbonates, reference is madeby way of example to “Schnell”, Chemistry and Physics of Polycarbonates,Polymer Reviews, Vol. 9, Interscience Publishers, New York, London,Sydney 1964, to D. C. PREVORSEK, B. T. DEBONA and Y. KESTEN, CorporateResearch Center, Allied Chemical Corporation, Moristown, N.J. 07960,“Synthesis of Poly(ester)carbonate Copolymers” in Journal of PolymerScience, Polymer Chemistry Edition, Vol. 19, 75-90 (1980), to D.Freitag, U. Grigo, P. R. Müller, N. Nouvertne, BAYER AG,“Polycarbonates” in Encyclopedia of Polymer Science and Engineering,Vol. 11, Second Edition, 1988, pages 648-718 and finally to Drs U.Grigo, K. Kircher and P. R. Müller “Polycarbonates” in Becker/Braun,Kunststoff-Handbuch, Volume 3/1, Polycarbonate, Polyacetale, Polyester,Celluloseester, Carl Hanser Verlag, Munich, Vienna 1992, pages 117-299.Production is preferably performed by the phase boundary method or themelt interesterification method and is described below using the phaseboundary method by way of example.

[0059] The compounds preferably used as starting compounds arebisphenols with the general formula HO—Z—OH, wherein Z is a divalentorganic radical having 6 to 30 carbon atoms and containing one or morearomatic groups.

[0060] Examples of such compounds are bisphenols belonging to the groupof dihydroxydiphenyls, bis(hydroxyphenyl)alkanes, indane bisphenols,bis(hydroxyphenyl)ethers, bis(hydroxyphenyl)sulfones,bis(hydroxyphenyl)ketones and α,α′-bis(hydroxyphenyl) diusopropylbenzenes.

[0061] Particularly preferred bisphenols belonging to the previouslycited group of compounds are bisphenol A, tetraalkyl bisphenol A,4,4-(metaphenylene diisopropyl)diphenol (bisphenol M),4,4-(paraphenylene diisopropyl)diphenol,1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (BP-TMC), optionallytogether with mixtures thereof.

[0062] Particularly preferred are homopolycarbonates based on bisphenolA and copolycarbonates based on the monomers bisphenol A and1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane. The bisphenolcompounds for use according to the invention are reacted with carbonicacid compounds, particularly phosgene or in the case of the meltinteresterification process diphenyl carbonate or dimethyl carbonate.

[0063] Polyester carbonates are obtained by reacting the previouslycited bisphenols, at least one aromatic dicarboxylic acid and optionallycarbonic acid equivalents. Examples of suitable aromatic dicarboxylicacids include phthalic acid, terephthalic acid, isophthalic acid, 3,3′-or 4,4′-diphenyldicarboxylic acid and benzophenone dicarboxylic acids. Aportion, up to 80 mol %, preferably from 20 to 50 mol % of the carbonategroups in the polycarbonates can be replaced by aromatic dicarboxylicacid ester groups.

[0064] Examples of inert organic solvents used in the phase boundarymethod include dichloromethane, the various dichloroethanes andchloropropane compounds, tetrachloromethane, trichloromethane,chlorobenzene and chlorotoluene, with chlorobenzene or dichloromethaneor mixtures of dichloromethane and chlorobenzene preferably being used.

[0065] The phase boundary reaction can be accelerated by catalysts suchas tertiary amines, particularly N-alkyl piperidines or onium salts.Tributylamine, triethylamine and N-ethyl piperidine are preferably used.In the melt interesterification process the catalysts cited in DE-A4238123 are preferably used.

[0066] The polycarbonates can be deliberately and controllably branchedby the use of small quantities of branching agents. Suitable branchingagents include: phloroglucinol,4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)heptene-2; 4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)heptane; 1,3,5-tri(4-hydroxyphenyl)benzene;1,1,1-tri(4-hydroxyphenyl)ethane; tri(4-hydroxyphenyl)phenyl methane;2,2-bis[4,4-bis-(4-hydroxyphenyl)cyclohexyl]propane;2,4-bis(4-hydroxyphenyl isopropyl)phenol;2,6-bis(2-hydroxy-5′-methylbenzyl)-4-methylphenol;2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane;hexa(4-(4-hydroxyphenyl isopropyl)phenyl) orthoterephthalic acid ester;tetra(4-hydroxyphenyl)methane; tetra-(4-(4-hydroxyphenylisopropyl)phenoxy)methane;α,α′α″-tris(4-hydroxyphenyl)-1,3,5-triisopropyl benzene;2,4-dihydroxybenzoic acid; trimesic acid; cyanuric chloride;3,3-bis(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole;1,4-bis(4′,4″-dihydroxytriphenyl)methyl)benzene and in particular:1,1,1-tri(4-hydroxyphenyl)ethane andbis(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole.

[0067] The 0.05 to 2 mol % of branching agents or mixtures of branchingagents that can optionally additionally be used, relative to thediphenols used, can be used together with the diphenols but are alsoadded at a later stage of the synthesis.

[0068] Chain terminators can be used. Phenols such as phenol, alkylphenols such as cresol and 4-tert-butyl phenol, chlorophenol,bromophenol, cumyl phenol or mixtures thereof are preferably used aschain terminators, in quantities of 1-20 mol %, preferably 2-10 mol %per mol of bisphenol. Phenol, 4-tert-butyl phenol or cumyl phenol arepreferably used.

[0069] Chain terminators and branching agents can be added to thesyntheses either separately or together with the bisphenol.

[0070] The manufacture of polycarbonates according to the meltinteresterification process is described in DE-A 4 238 123 by way ofexample.

[0071] Suitable UV absorbers for the compositions according to theinvention are preferably such compounds that because of their absorptioncapacity below 400 nm are capable of protecting polycarbonateseffectively against UV light and exhibit a molecular weight of over 370,preferably of 500 and above.

[0072] Suitable UV absorbers are in particular the compounds describedin WO 99/05205 with formula (II)

[0073] wherein

[0074] R¹ and R² are the same or different and denote H, halogen, C₁-C₁₀alkyl, C₅-C₁₀ cycloalkyl, C₇-C₁₃ aralkyl, C₆-C₁₄ aryl, —OR⁵ or—(CO)—O—R⁵ where R⁵=H or C₁-C₄ alkyl,

[0075] R³ and R⁴ are likewise the same or different and denote H, C₁-C₄alkyl, C₅-C₆ cycloalkyl, benzyl or C₆-C₁₄ aryl,

[0076] m is 1, 2 or 3 and n is 1, 2, 3 or 4,

[0077] and those with formula (III)

[0078]  where the bridge denotes

[0079] R¹, R², m and n have the meaning specified for formula (II),

[0080] wherein moreover p is a whole number from 0 to 3,

[0081] q is a whole number from 1 to 10,

[0082] Y is —CH₂—CH₂—, —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅—, —(CH₂)₆—, orCH(CH₃)—CH₂— and

[0083] R³ and R⁴ have the meaning specified for formula (II).

[0084] Further suitable UV absorbers are those that representsubstituted triazines, such as2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)-1,3,5-triazineCYASORB® UV-1164) or2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyl)oxyphenol (Tinuvin® 1577).Particularly preferred as UV absorber is2,2-methylene-bis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol),which is sold commercially under the name Tinuvin® 360 or Adeka Stab® LA31. The UV absorber Uvinul® 3030 from BASF AG obtained according to WO96/15102, example 1, is also suitable. The UV absorbers cited in EP-A 0500 496 and U.S. Pat. No. 5,959,012 are also suitable.

[0085] The UV absorbers are incorporated into the compositions accordingto the invention by conventional methods, for example by mixingsolutions of the UV absorbers with solutions of the plastics in suitableorganic solvents such as CH₂Cl₂, halogen alkanes, halogen aromatics,chlorobenzene and xylenes. The mixtures of substances are thenpreferably homogenised by extrusion by known means; the solutionmixtures are preferably removed by known means by evaporating thesolvent, followed by extrusion, for example compounding.

[0086] Suitable stabilisers for the polycarbonates for the compositionsaccording to the invention are for example stabilisers containingphosphines, phosphites or silicon and other compounds described in EP-A0 500 496. Examples to be mentioned include triphenyl phosphites,diphenyl alkyl phosphites, phenyl dialkyl phosphites,tris(nonylphenyl)phosphite,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylene diphosphonite andtriaryl phosphite. Triphenyl phosphine andtris(2,4-di-tert-butylphenyl)phosphite are particularly preferred.

[0087] The compositions according to the invention can further contain0.01 to 0.5 wt. % of (partial) esters of tetrahydric to hexahydricalcohols, particularly of pentaerythritol.

[0088] Examples of tetrahydric alcohols include pentaerythritol andmesoerythritol. Examples of pentahydric alcohols include arabitol,ribitol and xylitol. Examples of hexahydric alcohols include mannitol,glucitol (sorbitol) and dulcitol.

[0089] The esters are preferably the monoesters, diesters, triesters,tetraesters or optionally pentaesters and hexaesters or mixturesthereof, particularly random mixtures, of saturated aliphatic C₁₀ to C₂₆monocarboxylic acids, preferably with saturated aliphatic C₁₄ to C₂₂monocarboxylic acids.

[0090] The commercially obtainable fatty acid esters, particularly thoseof pentaerythritol, can contain up to 60% of various partial esters,depending on the production method.

[0091] Examples of saturated aliphatic monocarboxylic acids with 10 to26 C atoms include decanoic acid, dodecanoic acid, tetradecanoic acid,hexadecanoic acid, octadecanoic acid, eicosanoic acid, docosanoic acid,tetracosanoic acid and hexacosanoic acid.

[0092] Examples of preferred saturated aliphatic monocarboxylic acidswith 14 to 22 C atoms include tetradecanoic acid, hexadecanoic acid,octadecanoic acid, eicosanoic acid and docosanoic acid.

[0093] Saturated aliphatic monocarboxylic acids such as hexadecanoicacid and octadecanoic acid are particularly preferred.

[0094] The saturated aliphatic C₁₀ to C₂₆ carboxylic acids and the fattyacid esters according to the invention are either known per se from theliterature or can be produced by methods known from the literature.Examples of pentaerythritol fatty acid esters are those of theparticularly preferred monocarboxylic acids specified above.

[0095] Esters of pentaerythritol with octadecanoic acid and hexadecanoicacid are particularly preferred.

[0096] Examples of antistatics are cationic compounds, for examplequaternary ammonium, phosphonium or sulfonium salts, anionic compounds,for example alkyl sulfonates, alkyl sulfates, alkyl phosphates,carboxylates in the form of alkali-metal salts or alkaline-earth metalsalts, non-ionogenic compounds, for example polyethylene glycol esters,polyethylene glycol ethers, fatty acid esters, ethoxylated fatty amines.Preferred antistatics are non-ionogenic compounds.

[0097] All feedstocks and solvents used for synthesis of the coextrusioncompositions according to the invention can be contaminated withcorresponding impurities as a result of manufacture and storageconditions, the objective being to work with the cleanest possiblestarting materials.

[0098] The individual components can be mixed by known means, bothsuccessively and simultaneously, and at both room temperature andelevated temperature.

[0099] The additives are preferably incorporated into the compositionsaccording to the invention by known means by mixing polymer granuleswith the additives at temperatures from around 200 to 400° C. inconventional units such as internal mixers, single-screw extruders anddouble-shaft extruders, for example by melt compounding or meltextrusion or by mixing the polymer solutions with solutions of theadditives, followed by evaporation of the solvents by known means. Theproportion of additives in the moulding composition can be variedbetween broad limits and is governed by the desired properties of thecompositions. The total proportion of additives in the compositions ispreferably up to around 20 wt. %, by preference 0.2 to 12 wt. %,relative to the weight of the composition.

[0100] As is underlined by the examples according to the invention, theuse of the compositions according to the invention on any polycarbonatemoulding compositions as base material offers a significant advantage.The base material for the sheet can also be treated with the mouldrelease agent from the composition according to the invention.

[0101] The invention therefore also provides mouldings produced usingthe compositions according to the invention. The compositions can beused to produce solid plastic sheets and multi-wall sheets (e.g.twin-wall sheets). The sheets therefore also include those that displayon one or both sides an additional outer layer with the compositionsaccording to the invention having an elevated content of UV absorbers.

[0102] The compositions according to the invention simplify themanufacture of products, particularly of sheets and products producedtherefrom, such as glazing for greenhouses, conservatories, busshelters, advertising hoardings, signs, protective screens, automotiveglazing, windows and roofs.

[0103] Subsequent processing steps for products coated with thecompositions according to the invention, e.g. thermoforming or surfacetreatments, e.g. application of scratch-resistant coatings,water-spreading layers and similar are possible and the presentinvention likewise provides the products manufactured by these methods.

[0104] Coextrusion is known per se from the literature (see for exampleEP-A 0 110 221 and EP-A 0 110 238).

[0105] In the present case the procedure is preferably performed asfollows:

[0106] Extruders are connected to a coextrusion adapter to produce thecore and outer layer(s). The adapter is designed in such a way that themelts forming the outer layer(s) are applied adhesively as a thin layerto the melt of the core.

[0107] The multi-layer melt strand produced in this way is thentransferred to the adjacent die in the desired form (multi-wall sheet orsolid sheet). The melt is then cooled under controlled conditions byknown means by calendering (solid sheet) or vacuum calibration(multi-wall sheet) and then cut into lengths. A conditioning oven canoptionally be connected after the calibration stage to eliminatestresses. In place of the adapter connected before the die, the dieitself can also be designed in such a way that the melts are broughttogether there.

[0108] The invention is illustrated by means of the following example.

EXAMPLE

[0109] 10 mm twin-wall sheets A to F, such as are described for examplein EP-A 0 110 238, were obtained from the following compositions:Makrolon® KU 1-1243 (branched bisphenol A polycarbonate from Bayer AG,Leverkusen, Germany, with a melt flow rate (MFR) of 6.5 g/10 min at 300°C. and 1.2 kg load) was used as base material. This was coextruded withthe compounds listed in the table and based on Makrolon® 3100 (linearbisphenol A polycarbonate from Bayer AG, Leverkusen, Germany, with amelt flow rate (MFR) of 6.5 g/10 min at 300° C. and 1.2 kg load).

[0110] The thickness of the coextrusion layer was around 50 μm in eachcase. Sheet UV absorber Mould release agent A 5 wt. % Tinuvin 360 0.2wt. % according to invention*) B 5 wt. % Tinuvin 360 0.3 wt. % accordingto invention*) + 0.1 wt. % PETS**) C 5 wt. % Tinuvin 360 0.1 wt. %according to invention*) + 0.1 wt. % PETS**) D 5 wt. % Tinuvin 360 0.2wt. % 2-octyldodecyl-12-stearoyl stearate****) E 5 wt. % Tinuvin 3600.25 wt. % PETS**) F 5 wt. % Tinuvin 360 0.1 wt. % PETS**) + 0.05 wt. %GMS***)

[0111] The machines and equipment used to produce multi-layer multi-wallsheets are described below.

[0112] The apparatus consisted of

[0113] the main extruder with a screw of length 33 D and a diameter of70 mm with venting

[0114] the coex adapter (feedblock system)

[0115] a coextruder for applying the outer layer with a screw of length25 D and a diameter of 30 mm

[0116] the special sheet extrusion die with a width of 350 mm

[0117] the calibrator

[0118] the roller conveyor

[0119] the take-off unit

[0120] the flying knife (saw)

[0121] the stacking table.

[0122] The polycarbonate granules forming the base material weresupplied to the feed hopper for the main extruder, the UV coextrusionmaterial to that for the coextruder. In each case the material is meltedand conveyed in the corresponding cylinder/screw plasticising system.Both material melts were brought together in the coex adapter and formeda composite after leaving the die and being cooled in the calibrator.The other equipment served to transport, cut to length and stack theextruded sheets.

[0123] Coextrusion with D (Reference):

[0124] first minor deposits after 4 hours

[0125] slight transverse waves appearing after 90 minutes at irregularintervals, which have a slightly negative influence on the sheetquality.

[0126] Somewhat stronger transverse waves after 4½ hours.

[0127] rating: good

[0128] Coextrusion with E (Reference):

[0129] first minor defects after 50 minutes (transverse waves, smallwhite blisters)

[0130] more significant defects after 90 minutes (warping ofcross-pieces, white deposits, transverse waves)

[0131] rating: poor

[0132] Coextrusion with F (Reference):

[0133] first minor defects after 90 minutes (small white blisters)

[0134] more significant defects after 100 minutes (warping ofcross-pieces, white deposits)

[0135] rating: satisfactory to poor

[0136] Coextrusion with A:

[0137] no deposits over a test period of 5 hours

[0138] slight transverse waves appearing after 90 minutes at irregularintervals, which have a slightly negative influence on the sheet quality

[0139] rating: very good

[0140] Coextrusion with B:

[0141] no deposits over a test period of 5 hours

[0142] slight transverse waves appearing after 90 minutes at irregularintervals, which have a slightly negative influence on the sheet quality

[0143] rating: very good

[0144] Coextrusion with C:

[0145] no deposits over a test period of 5 hours

[0146] slight transverse waves appearing after 90 minutes at irregularintervals, which have a slightly negative influence on the sheet quality

[0147] rating: very good

1. Compositions containing polycarbonate and one or more differentcompounds with the general formula (I)

wherein a equals 1 to 20 b equals 1 to 25 and c equals 10 to
 40. 2.Compositions according to claim 1 that additionally contain one or moredifferent compounds with the general formula (I)

wherein a equals 0 b equals 1 to 25 and c is 10 to
 40. 3. Compositionsaccording to claim 1 or 2, whereby the proportion of compounds accordingto formula (I) is 0.02 to 1.0 wt. %.
 4. Compositions according to claim1 or 2, whereby the compositions additionally contain 0.01 to 0.5 wt. %of esters or partial esters of tetrahydric to hexahydric alcohols. 5.Compositions according to any one of claims 1 to 4, whereby thecompositions additionally contain 0.1 to 15 wt. % of UV absorbers. 6.Compositions according to claim 5, whereby the UV absorber is chosenfrom the group consisting of(bis[2-hydroxy-5-tert-octyl-2-(benzotriazol-2-yl) phenyl]methane),2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyl)oxyphenol and2-cyano-3,3-diphenyl propenoicacid-2,2-bis[[2-cyano-1-oxo-3,3-diphenyl-2-propenyl)oxy]methyl]-1,3-propanediylester.
 7. Compositions according to any one of claims 1 to 6, wherebythe compositions additionally contain 10 to 3000 ppm of heatstabilisers, relative to the total quantity of the composition. 8.Compositions according to claim 7, whereby the heat stabiliser is chosenfrom the group consisting of tris-(2,4-di-tert-butylphenyl)phosphite andtriphenyl phosphine.
 9. Use of compounds with the general formula (I)

wherein a equals 1 to 20 b equals 1 to 25 and c is 10 to 40, in themanufacture of compositions containing polycarbonate and compounds withthe general formula (I).
 10. Use of the compositions according to anyone of claims 1 to 8 in the manufacture of products containing thesecompositions.
 11. Process for the manufacture of products containing atleast one outer layer containing compositions according to any one ofclaims 1 to 8 by extrusion or coextrusion.
 12. Products containingcompositions according to any one of claims 1 to
 8. 13. Sheets, roofs orglazing systems containing compositions according to any one of claims 1to
 9. 14. Multi-layer product comprising a first layer containingpolycarbonate and a second layer containing a composition according toany one of claims 1 to
 8. 15. Process for the manufacture of multi-layerproducts according to claim 14 by coextrusion.
 16. Greenhouse,conservatory, bus shelter, advertising hoarding, sign, protectivescreen, automotive glazing, window or roof containing a multi-layerproduct according to claim 14.